DESCRIPTION (provided by candidate): Cystic Fibrosis (CF) is the most common inherited disorder among Caucasians, 1/2500 births (1). Current management of Cystic Fibrosis (CF) entails treatment with antibiotics, airway clearance, nutrition, and management of pulmonary exacerbations. Over the past several decades, the improvements in clinical care have greatly improved the outlook for patients with CF, as evidenced by improvement in survival and the growing adult CF population (1). The median predicted survival in 1970 was 16 years old, and now is over 37 years old (1, 2). However, currently patients with CF have no objective way of monitoring their disease status at home, and only seek care after symptoms have developed. Other patient populations who perform home monitoring (diabetics, asthmatics, and lung transplant recipients) have improved mortality and morbidity rates (3-5). However, no such techniques have been accepted for patients with CF (1). CF patients suffer from frequent pulmonary exacerbations, and treatment with antibiotics and/or hospitalization is often required, leading to a faster decline in lung function compared to normal individuals (1). In addition, early and aggressive care is associated with improved health outcomes (6). Preliminary data shows that we can detect pulmonary exacerbations before patients have worsening symptoms. Our study uses home FEV1 (measure of lung function) and symptom monitoring, and our long term objectives are to detect exacerbations earlier, prevent exacerbations, and slow the rate of decline in lung function. AIM 1: To identify patterns of FEV1 that predict the development of a pulmonary exacerbation. AIM 2: To examine the effects of home spirometry and symptoms monitoring on the rate of annual decline in FEV1. Hypotheses: Home FEV1 and symptoms monitoring will identify patterns of FEV1 variability that predict the onset of a pulmonary exacerbation and will result in a slower annual decline in FEV1. Research Design/Methods: 156 individuals with CF will be recruited from the Johns Hopkins Pediatric and Adult CF clinics and randomized to either home monitoring or standard care arms. The home monitoring group will be provided with the Jaegar AM2 Lung function monitor (7), which will record their FEV1 twice daily and symptoms once daily (using 8 questions). Data will be transmitted weekly by telephone modem. A pulmonary exacerbation score will be calculated and patients will be called who are flagged as having an exacerbation. Both groups will be advised on treatment using the same antibiotic protocol. Outcomes that will be measured include rate of pulmonary exacerbations and change in FEV1 over 2 years. This is relevant to public health because we hope to improve survival and quality of life in patients with CF.